#include <stdlib.h>
#include <ctype.h>

long long atoll(const char *s)
{
    long long n=0;
    int neg=0;
    while (isspace(*s)) s++;
    switch (*s) {
    case '-': neg=1;
    case '+': s++;
    }
    /* Compute n as a negative number to avoid overflow on LLONG_MIN */
    while (isdigit(*s))
        n = 10*n - (*s++ - '0');
    return neg ? n : -n;
}
